1. Field of the Invention
This invention relates to apparatus for the chemical analysis of substances, and more particularly to a mechanism for delivering an analysis slide to a plurality of modular elements in a chemical analyzer.
2. State of the Prior Art
Recent developments have provided analysis slides for use in performing quantitative analyses of biological fluids. The slides are essentially planar, contain reagents in dry form, and can be loaded into a cartridge for use in a chemical analyzer. In the operation of such an analyzer, an analysis slide is fed from a cartridge into a metering station where a predetermined amount of sample fluid is deposited on the analysis slide. After an appropriate incubation period, the slide is moved to an analysis station where a change in the slide is sensed, the amount of change being proportional to a particular analyte in the sample fluid. The slide is used only once and is discarded after the reading has been taken. An analyzer for use with slides of this type is described in commonly-assigned U.S. Pat. No. 4,152,390, granted on May 1, 1979.
There is a growing trend in the clinical apparatus field toward analyzers which include a plurality of removable modules. The use of modules permits an analyzer to be easily modified to fit the needs of a particular user, and it also facilitates maintenance of the analyzer in that modules can be exchanged rather than repairing a module on the analyzer. In such apparatus, there is a problem in insuring that the modules installed on the apparatus are properly aligned with other apparatus elements which interfere with the modules. The alignment problem is especially critical when relatively small, light objects must be transferred from one module to another. Although it is possible to align the various modules of an analyzer by a trial-and-error method, this is very time consuming; further, the modules can become misaligned during operation of the analyzer due to wear and vibration.
Slide handling apparatus is known in clinical apparatus for transferring slides between permanently mounted elements of the apparatus. For example, the patent to Binnings et al., U.S. Pat. No. 3,650,437, discloses apparatus having a slide distributor in the form of a turntable which is adapted to advance slides through a series of stations in the apparatus. The turntable comprises a plurality of pivotally mounted slide holders spaced around its outer periphery. At certain points in the operating cycle, the slide holders engage a fixed ramp, or cam, which pivots the slide holder and the slide carrier thereon to an angular position in which certain operations are performed on the slide. There is no suggestion, however, in the Binnings et al. patent of a solution to the problem of aligning a slide transport device with removable modular elements.
Slide handling mechanisms are also found in the photographic art, although none of the known mechanisms include means for transferring slides between removable modules. Representative of the mechanisms in the photographic art is the patent to Costanza et at., U.S. Pat. No. 3,659,934, which discloses a slide projector having a slide supply magazine supported above a turntable. Slides are fed from the magazine onto the turntable which moves the slides into a position for projection; after projection, the turntable moves the slides into a receiving chamber where the slides are collected for eventual restacking in a supply magazine.